And convey good news to those who believe and do good deeds, that they shall have gardens in which rivers flow; whenever they shall be given a portion of the fruit thereof, they shall say: This is what was given to us before; and they shall be given the like of it, and they shall have pure mates in them, and in them, they shall abide.
Al-Baqra Verse 25
Allah's Apostle said, "Whenever you hear the Adhan, say what the Mu'adhdhin is saying.
Sahih Bukhari: Volume 1, Book 11, Number 585